oss-sec mailing list archives
Re: [Security] /proc infoleaks
From: Sebastian Krahmer <krahmer () suse de>
Date: Tue, 7 Sep 2010 13:13:45 +0200
On Tue, Sep 07, 2010 at 03:51:03AM -0700, Andrew Morton wrote:
On Tue, 7 Sep 2010 10:35:46 +0200 Sebastian Krahmer <krahmer () suse de> wrote:I have been elected to receive the bashing from all sides, so here we go. It is not about a new vulnerability or even a new discussion but needs to be discussed, at least that we have a clear statement about the status quo. Recent i-CAN-haz-MODHARDEN.c has shown once *again* that certain file permissions make no sense except to exploitation development. There is no reason to have files like /proc/kallsyms /proc/slabinfo /proc/zoneinfo and probably a lot of others world readable. The symbol addresses might be hard-coded for a certain targetlist inside the exploit so you can argue that there wont be any protection benefit from making it unreadable. However this argument aint a reason to also leak it for self-compiled kernels and doesnt even hold for dynamic/runtime content like slabinfos etc. It would be nice to have something like echo 1 > /proc/quiet or something like a umask for kernel-owned proc entries so that you have a polite default and are still able to enable it for certain profiling tools or whereever you need it.chmod 0440 /proc/slabinfo
Heh, indeed. :-) Would it be a bad idea to have proc_create() use a more strict mode so it is non-leaking by default? Sebastian -- ~ ~ perl self.pl ~ $_='print"\$_=\47$_\47;eval"';eval ~ krahmer () suse de - SuSE Security Team ~ SUSE LINUX Products GmbH, GF: Markus Rex, HRB 16746 (AG Nuernberg)
Current thread:
- /proc infoleaks Sebastian Krahmer (Sep 07)
- Re: [Security] /proc infoleaks Andrew Morton (Sep 07)
- Re: [Security] /proc infoleaks Sebastian Krahmer (Sep 07)
- Re: Re: [Security] /proc infoleaks Marcus Meissner (Sep 07)
- Re: [Security] [oss-security] Re: /proc infoleaks Willy Tarreau (Sep 13)
- Re: [Security] /proc infoleaks Sebastian Krahmer (Sep 07)
- Re: Re: [Security] /proc infoleaks Jon Oberheide (Sep 07)
- Re: Re: [Security] /proc infoleaks Andrew Morton (Sep 07)
- Re: [Security] [oss-security] Re: /proc infoleaks Andrew Morton (Sep 07)
- Re: [Security] [oss-security] Re: /proc infoleaks Brad Spengler (Sep 07)
- Re: Re: [Security] [oss-security] Re: /proc infoleaks Sebastian Krahmer (Sep 07)
- Re: Re: [Security] [oss-security] Re: /proc infoleaks Brad Spengler (Sep 08)
- Re: [Security] /proc infoleaks Andrew Morton (Sep 07)
- Re: [Security] [oss-security] Re: /proc infoleaks Linus Torvalds (Sep 07)